In those patients with ER + BC who did not receive endocrine therapy, high SLC39A6 protein expression remained its association with longer BCSS (P = 0.001, HR 0.701, 95% CI 0.463‒1.062; Supplementary Fig. 7) and DMFS (P = 0.027, HR 0.784, 95% CI 0.533‒1.151; Supplementary Fig. 8) compared to patients with low SLC39A6 expression. Here, SLC39A6 is linked to breast cancer.